Well that spidey's way is useless because it rarely ever works. If you do this it will work unless the pack itself is broken.

First you download the file, (duh)

Second you open it up, (still duh)

Third when you open it up it should have folder names| I.E: materials.

Fourth when you see that folder, you open up your garrysmod folder
C:/Program Files/Steam/steamapps/(steam name here)/garrysmod/garrysmod

If it says materials you find the "materials" folder in this area and take everything in the materials folder from the download, and paste it into there.

If it ever asks you to replace a folder, never do so, just find that folder it wants you to replace and paste everything in there.

the real way *smiles*

yeah well thanks

thanks what?